Controlled gelation in aqueous explosives containing boric acid

ABSTRACT

Explosive compositions containing boric acid, a gelling agent, an oxidizer, a fuel component, and an aqueous medium and a method of controlling the degree of gelation of these compositions. The compositions can be gelled to the extent desired by adjusting their pH.

United States Patent [151 3,653,996

Edwards 1 Apr. 4, 1972 [54] CQNTROLLED GELATION IN AQUEOUS EXPLOSIVESCONTAINING References Cited UNITED STATES PATENTS [72] Invent: Edwards3,072,509 l/l963 Barnhart et a1. ..149/92 x [73] Assignee: AtlasChemical Industries, Inc., Wilming- 3,330,706 7/1967 Griffith ..149/44 Xton, Del, Primary ExaminerLeland A. Sebastian [22] Flled' 1970AttorneyKenneth E. Mulford, Roger R. Horton and Ernest [21] Appl. No.:5,144 G. Almy 52 us. Cl ..149/21, 149/2, 149/38, [57] ABSTRACT 14 l /44,Explosive compositions containing boric acid, a gelling agent, l4 7; '1an oxidizer, a fuel component, and an'aqueous medium and a 149/77,149/78, 149/89, l l49/105 method of controlling the degree ofgelation ofthese composi- [51] Int. Cl. ..C06b 19/04 tions. The compositions can hegelled to the extent desired by [58] Field of Search ..149/92; 149/2,21, 38, 41, adjusting their PH 27 Claims, N0 Drawings CONTROLLEDGELATION IN AQUEOUS EXPLOSIV ES CONTAINING BORIC ACID This inventionrelates to explosive compositions which are capable of controlledgelation and to a method of controlling the degree of their gelation.

Slurry explosives generally contain a gelling agent such as guar gum toprevent the insoluble components of the explosive from segregating,which would make the explosive insensitive. A cross-linking agent isusually also present to crosslink the gelling agent and form a stablegel; generally, borates and chromates are used as cross-linking agents.These compounds form cohesive gels between a pH of about 5 to about 6.Below about 5 only a thickened mass is produced, and above about 6 thegel becomes so tight that the water is squeezed out. With certain typesof gums, a gel cannot be formed at all even at a high pH. But even at apH of 5 to 6, these gels are not pourable and there is no way to controlor vary the degree of gelation. As such, they are difficult to load intoa borehole and do not adequately fill all the voids in the borehole,which may result in an inefficient utilization of the explosive.

Since most gelling agents require time to gel, the commercial practiceis to use excess gelling agent so that the gelation is complete enoughat the end of the mixing stage to prevent segregation of the components.However, in addition to producing gels which are not pourable, thispractice may also produce gels which are so tight that the water issqueezed out leaving the explosive insensitive.

An explosive composition can be gelled with small amounts of gellingagents by heating during the mixing stage in an attempt to enhancecross-linking of the gel prior to storage. Normally, heat alone will notcomplete all of the cross-linking available from the conventionalgelling agents present in the formulation. Thus, additional crosslinkingtakes place during storage with the possibility of ingredient separationdue to the incomplete initial gelation.

ADVANTAGES OF THE INVENTION l have discovered explosive compositionswhich can be made to have any desired degree of gelation simply bycontrolling their final pH. A gelled explosive composition can be madewhich is tight enough so that the components of the explosive do notsegregate on storage, yet is pourable and has good bag release, and thepreferred compositions do not gel significantly further on storage.Moreover, gels can be formed at a pH as low as 5 in the compositions ofthis invention using as gelling agents those gums which would previouslygel only at at higher pH.

But the most remarkable property of the compositions of this inventionis the ease with which the degree of gelation can be controlled. Whileprior art gels, once formed, cannot be easily ungelled, the gels of thisinvention can be repeatedly made tighter or weaker by successiveadjustments of their pH.

COMPOSITIONS OF THIS INVENTION The explosive compositions of thisinvention comprise a gelling agent, boric acid, an aqueous medium, anoxidizer, and a fuel component. An explosive composition may be formedfrom 1 part by weight (pbw) oxidizer, about 0.14 to 0.43 pbw water,about 0.007 to 0.4 parts per part ofwater ofa two-component mixtureabout 20 to 80 percent of which is a boric acid and about 20 to 80percent of which is a gelling agent and a sufficient amount of a fuelcomponent to give an oxygen balance between about +10 and 30. Theexplosive composition also preferably contains about 0.7 to 2.5 pbw of asensitizer.

Boric acid is the cross-linking agent and is the component of thecompositions of this invention which gives them their unusualproperties. As smaller and smaller amounts of boric acid are used, thegel becomes thinner and thinner; the full range of gelation from a verythin to a tight gel may be obtained if the amount of boric acid used isequal to at least about 25 percent of the amount of gelling agent used.Excessive amounts of boric acid do not appear to be harmful, but merelyunnecessary.

The boric acid is preferably obtained directly from boric acid, B(OH)but may also be obtained from boron compounds which can be substantiallydissociated into boric acid. Such compounds include borax, metaboricacid and the metaborates, alkyl boric acids such as butylboric acid,aromatic boric acids such as phenyl boric acid, sodiumtetramethoxyborate (borine), boron halides such as boron trichloride andboron tribromide, and boron sulphide.

The gelling agent is a substance, usually polymeric, which is capable ofbeing cross-linked in water to form a gel which is stable in thepresence of the oxidizer. The gelling agent is preferably apolysaccharide, preferably a galactomannan such as locust bean gum orguar gum, but may also be a gelling agent such as a biopolymer. Guar gumis usually preferred because of its availability.

The oxidizer is the source of oxygen during the explosion and ispreferably ammonium nitrate. However, other inorganic oxidizer saltssuch as sodium nitrate, calcium nitrate, magnesium nitrate, potassiumnitrate, lithium nitrate, ammonium chlorate, potassium chlorate, sodiumchlorate, ammonium perchlorate, potassium perchlorate, or sodiumperchlorate may also be used.

The fuel component is a substance which consumes oxygen during theexplosion. This definition would include the components which functionas a gelling agent as well as many components which function assensitizers. In addition, materials may be added primarily for thepurpose of consuming oxygen such as sulfur, coal, bagasse, fuel oil,parafiin oil, etc.; sulfur is preferred. Liquid fuels such as ethyleneglycol, formamide, or glycerine may also be used either to reduce theamount of water or to promote low-temperature pourability.

A sensitizer is a substance which increases the sensitivity of acomposition and includes explosive compounds, air-entrapping materials,and finely divided metals. Explosive sensitizers include, for example,nitroglycerin, TNT, DNT, tetryl, RDX, PETN, nitromethane, and aminenitrates such as methyl amine nitrate and ethylene diamine dinitrate.Examples of airentrapping materials include expanded perlite and glass,ureaformaldehyde and phenol formaldehyde micro-spheres. Aluminum andmagnesium, for example, may be used as finely divided metal sensitizers.A combination of an air-entrapping material and an explosive sensitizeris preferred because it produces the greatest sensitivity.

Other compounds may also be included in the compositions for variouspurposes, such as surfactants to help promote the gelling process.

METHOD OF CONTROL The present invention contemplates control over thedegree of gelation of gelling agent, water, and boric acid compositionsby adjusting the pH of the composition. Essentially, one first preparesa mixture containing at least the boric acid, the gelling agent, and theaqueous medium, although the mixture may also contain other componentsof the composition. The pH is adjusted to the final pH with a base or anacid, for example, ammonium hydroxide or acetic acid, and any remainingcomponents are mixed in. Alternatively, the boric acid may be addedafter the pH is adjusted to the final pH, but it is preferably to addthe boric acid before the final pH adjustment so that one may observethe degree of gelation as one adjusts the pH.

The final pH determines the properties of a given composition. Thehigher the final pH, the tighter will be the gel, and the lower thefinal pH, the more fluid will be the gel; also, the gel is more adhesiveat lower pH levels and, therefore, will give better release from aplastic bag at higher pH levels. It is preferable to start at a low pH,say, at most about 4.5, and to raise it to the final pH rather thanstarting at a high pH and lowering it to the final pH because it is mucheasier to disperse any insoluble materials in a thin gel than in a tightgel.

Generally, a final pH above about 7 is undesirable because the gel is sotight that water squeezes out. the components COMMENTS FOR TABLES 1 ANDll separate, and it is not pourable and has no water-resistance; Q gelhowever, it is still detonable. Also, a final pH less than about 2 CThim nonwhesive gel is generally undesirable because a thickened massresults 5 D Thin, pourable gel rather than a gel; it has nowater-resistance either but is still 5 e my detonable. For best results,the final pH should be between 4.5 g zx szgig gel system and 7, althoughthese limits will vary with the composition H Tight gel not pourablcused; a pH between 5.0 and 6 is the preferred range. Provided y f the 1fthe composition contains a liquid which 15 not easily 10 2 g zzgh ishzzfi Culncundenhc gelled such as some olly fuels, for example, fueloil, paraffin lmdemarkX058? oils, and particularly nitroparaffins suchas nitromethane, the 3. Sold by General Mills, Inc. under the trademarkbest procedure is to prepare a mixture containing at least the boricacid, the gelling agent, the aqueous medium, and the 2 23831?" liquidnot easily gelled. The pH is lowered to about 1.5 to 4.4, 5. An anionicheteropolysaccharide produced by the and the mixture is blended well andpreferably heated. The pH fermentalion Ufa Carbohydrate y bacterium isthen adjusted to the final pH. fic n 'fi s: 22 ge Generally, heatingduring mixing is desirable as it decreases J "adcmark the time necessaryto form a gel; 100 to 180 F. is a suitable Polyhall M-295" range but 140to 150 F. is preferred If explosive components g g fqz' xgi zg g mszg'geanal sis are used which are heat-sensitive, the composition should Labcm 335 percent boric acid t, either be heated and cooled before theexplosive components percent guar gum, about 22.9 percent water, areadded 01' Should not be heated, about 6.7 percent polyacrylamide, andabout Ll It is also preferable to add any large, solid materials such as25 pmbab'y "glycmde prills after the final pH adjustment since the gelhas formed by then and will prevent their segregation. The compositionsA to R of Tables 1 and 11 were prepared If a boron compound whichdissociates into boric acid by mixing the ammonium nitrate and ethylenedlamlhe under the conditions of this invention is used, the boroncomdihhrate Solutions, 'f to to i f P pound should be added to thegelling agent under conditions Posltioh H heauhg was h lrf mhlhg Intothe which prevent its reaction with the gelling agent prior to dis-50mm) 3 P of olhel: l The P of the sociation. Some boron compounds suchas the metaborates resulting h h adjustefj wlth acetic acld to ahou}dissociate rapidly enough that the conditions of reaction aretheh'l'alseld W1th afhmohlum hydroxlde over f e-" sufficient for theiruse and no special conditions are necessary. Penod h Shmhg the gelformed p h h was Others such as borax and the biborates require time todis- Prepared the Same mahher except the he was sociate and should beacidified prior to being mixed with the added after the final PHadlhstmehte eompesmohs were gelling agent. In addition, a compositionusing borax may tend stored at tempemhh'e venous the to vary in pH withtime and require adjustments to keep the test? were tefmlnaiefl at hlast reading. The ammon um and PH below 7 sodium salts of boric acidwere prepared by neutralizing a EXAMPLES 40 saturated solution of boricacid with ammonium and sodium hydroxides to a pH of 10 to 1 1,respectively, and evaporating Tables I and 11 below show the types ofgelation which to dryness; these salts apparently did not immediatelyrevert to resulted when various compositions were prepared and stored:boric acid in solution (compositions O and P).

TABLE I Composition, percent; A B C D E F G H I J 6 Ammonium nitratesolution 77.05 77.05 77. 05 77.05 77. 05 77.05 77.05 77.05 77.05 77. 05Ethylene diamine dinitrate s01uti0n. 21.25 21.25 21.25 21.25 21.25 21.2521.25 21.25 21.25 21.25 Boric acid 0.78 0.71 0. 69 0.69

Ammonium biborate (NH4HB4O7.3H2O)..-. Borax (NfizBiO'iJUHzO) a aAcidificd borax Non-ionic Guar gum L... Modified Guar gum...Polysaccharide Bio-polymer Polyacrylamide Final pH TAB LE IIComposition, percent K Ammonium nitrate solution"... 50% Ethylenediamine dinitratc solutiolL. Boric acid Ammonium salt of boric acidSodium salt of boric acid Sodium metaborate (NazBzO4.8HzO) BoricAcid-Gum-Amide-Ester Mixture 7 Noni0nlc Guar gum Modified Guar gum.Locust Bean gum Polysaccharide Polyacrylamide Final pH Freshha.

7 days M N O P Q R S As to the compositions of this invention (F to S),the rise in pH produced a corresponding increase in the degree ofgelation. As to composition E, once a gel had formed, a further increasein pH had no noticeable effect. Table I shows, inter Composition L wasprepared by mixing the nitrates, dinitrate, and the water, heating to160 F and adjusting the pH to 4.0 with acetic acid. The air-entrappingspheres, sulfur, gelling mixture, and boric acid were blended and theheated alia, that the preferred composition H withstood 120 days of 5nitrate solution was added incrementally while the temperastoragewithout further gelation occurring, while prior art ture was maintainedat 145 F. The surfactant was added and composition E formed a tight gelwithin an hour. Compositi the pH adjusted to 4.5 to 5.0 with sodiumhydroxide solution. E contrasts markedly with composition P where theborax was The nllfemethane and ethylene g y Wer e mixed and thedissolved in water and acidified with nitric acid to a pH of P wasadjusted to the hhalPH whh sofhum hydroxlde about 1.0 to dissociate itinto boric acid before it was added to composltlon M was P p by mlxlhgthe Sodium and the gelling agent. Although the non-preferredcomposltlons of monium h h Water at 150 The P was l T this invention (1and J) did not exhibit extended storage sta- 3 m 4 f e l and 9 and hon;acld bility, their degree of gelation was nevertheless pH sensitive.were mlxed fh h: The epp h p Sulfur Another composition identical tocomposition R was and ethylene dlamlne dinitrate were mlxed 1n and thepH adprepared in the same manner as composition S. The pH of this lhstedto 4 sodium hydroxide- The ethylehe glycol and composition was thensuccessively adjusted up and down with hmomefhane fvefe added nd thefinal pH ad ustment was acetic acid and ammonium hydroxide. Thefollowing degrees made Sodlum q'P of gelation were observed atsuccessive pH values: f composmons were poumble' and most ofcomposltlons (H, l, and K, for example) are pourable at low temperatures(20 to 30 F.); all the compositions had an oxpH Degree of Gelatlon ygenbalance between +10 and 30. The composltlons were 3 9 TH k d placed in 3inch diameter plastic cartridges and were L we mass detonated with a 3inch X 6 inch 75 percent gelatin dynamite.

. oose gel. very tacky I 5.3 Excellent pourability, tacky (poor release)what 15 clalrhed 1S: h 5.2 Excellent pourability, good release 1. Anexploslve composition comprlsing boric acid, a gelling f P h agent, anaqueous medium, an oxidizer, and a fuel component. slightly Wmammy lease2. A composition according to claim 1 which contains a sen- 6.6 Tlghtgel, not pourable, breaks apart easlly 6.0 Good pourability. excellentrelease sltlzer' 4 5.25 Excellent pourability, tacky 3. The compositionof dam 1 wherein said boric acid lS ob- 9 s y tacky tained by acidifyingborax. Tl'mkened 4. The composition of claim 1 wherein said gellingagent is a 6.9 Tight gel, not pourable. breaks apart easlly, watersqueezed polysaccharlde. I 4 so Good pourability, excellent release 5.The composltlon of claim 4 wherein said polysaccharlde 4.75 Loose "'3' his a galactomannan. "lease 6. The composition of claim 5 wherein saidgalactomannan 3.5 Thlckened mass 5.75 Excellent puurahility, goodrelease ls guar 7. An ex loslve com osltlon com rlsln l bw oxldlzer,

P P P 8 P about 0.14 to about 0.43 pbw water, about 0.007 to about 0.4Table lll below shows additional explosive compositions parts per partof water of a two-component mixture about 20 prepared according to thisinvention. to percent of which is boric acid and about 20 to 80 per-Composition, percent A B C D E F G H I I K L M Ammonium nitrate 41. 536. 2 31. 2 40. 7 39. 2 34. 2 .2 47. 05 43. 3 42. J Sodium nitrate 18.011.0 11.0 16. 0 11.0 11,0 .0 10.0 10.0 Calcium nitrate 5. 0 5. 0 5. 0 5.0 .0 Gelling mixture 2 1. 1 0.9 0. 9 0. 9 0. 0 0. 9 .9 0. 35 0.6 1. 1Bolic acid v 0. 5 0. 6 Water 14. 0 20.0 20.0 18.0 20. 0 20. 0 .0 20. 020. 0 20. 0 Ethylene glycol 7. 5 7. 5 7.5 7, 5 .5 10.0 5. 0 b. 0Surfactant 3 0 4 0. 4 0. 4 0. 4 0. 4 0. 4 .4 0. 6 0. 5 l. 0 Sulfur 3.03.0 2.0 3. 0 3. 0 .0 3. O 3. (J 3.0

Aluminum. Air'entrapping spheres 2.0 3 .0 3.0 2.0 2.0 Ethylene diarninedinitrtc. 5. 10.0 5. 0 5. 0 Nitromethane 0 15.0 10. 0 10.0

Nitrostarch T .N.T Final pH nt 5.55 5.8 5.0 5. 5.7 6.1 5. 75 5.85 Dens1ty,g./cc. 1.47 1.46 1.44 1.40 1. 26 1. 28 nt 1.1 1. 22 1.25 1. '20 1. 20eloclty, i.p.s 16,200 12,195 11,900 17, 090 16,340 16,025 17,045 14,23517.005 17.360 17.360 17.010 1 670 nt=Not tested.

1 Phenol formaldehyde in I), E, F, G, I, and J; glass in H, K, L, and M.9 41.7% bone acid, 49.2% guar gum, 9.2% polyacrylamide in A to K; 50-50mixture of.laguar and Jaguar DE," non-ionic guar gums sold by Stein.Hall 8; Co., Inc. in L; 50% boric acid and 50% Jaguar 100 in M.

3 Polyoxyethylene alkyl amine sold by Atlas Chemical Industries, Inc.under the trademark (ll-3780A.

In table "I, compositions A to K were prepared by mixing the water,surfactant, and the nitrates and dinitrate at to F. The pH was adjustedto 2 to 3 and the nitrostarch and TNT were added where used; afterstirring the aluminum was added (composition G). A pre-mix containingthe resin spheres, sulfur, and the gelling mixture was prepared andadded with stirring. When the compositions began to thicken, the pH wasadjusted with acetic acid to 3.5 to 4.5, and the ethylene glycol andnitromethane were added and stirred in for 1 minute where used. The pHwas then adjusted with ammonium hydroxide to the final pH whichinstantly resulted in the formation of the gel. Whole ammonium nitrateprills were then stirred in, 15 percent (this percentage is included inthe figure given in Table III for ammonium nitrate) in cases B and C; 10percent in case E; and 5 percent in cases H, J, and K.

cent of which is a gelling agent, and a sufficient amount of a fuelcomponent to give an oxygen balance between about +10 and -30.

8. The composition of claim 7 wherein said boric acid is obtained byacidifying borax.

9. A composition according to claim 7 wherein about 0.007 to about 2.5pbw of a sensitizer is present.

10. A composition according to claim 9 wherein said sensitizer is acombination of an air-entrapping material and an explosive.

11. The composition of claim 10 wherein said air-entrapping material isphenol formaldehyde or glass microspheres.

12. The composition of claim 7 wherein said gelling agent comprises apolysaccharide.

13. The composition of claim 12 wherein polysaccharide is agalactomannan.

14. The composition of claim 12 wherein said galactomannan is guar gum.

15. A method of controlling the degree of gelation of an explosivecomposition comprised of boric acid, a gelling agent, and water,comprising raising the pH of said composition to increase the degree ofgelation and lowering the pH to decrease the degree of gelation.

16. The method of claim 15 wherein said pH is adjusted to about 4.5 to7.

17. The method of claim 16 wherein said composition contains an oxidizerand a fuel component and is detonable.

18. The method of claim 17 wherein said gelling agent comprises apolysaccharide.

19. The method of claim 18 wherein said polysaccharide is aglactomannan.

20. The method of claim 19 wherein said galactomannan is guar gum.

21. The method of claim 17 wherein the pH is adjusted by lowering it tobelow about 4.5 and then raising it until a gel of the desiredconsistency is obtained.

said

22. The method of claim 17 wherein said composition is heated whilebeing gelled.

23. The method of claim 22 wherein said composition is heated to to F.

24. A method of controlling the degree of gelation of an .explosivecomposition which comprises boric acid, a gelling agent, an aqueousmedium, an oxidizer, a fuel component, and a liquid not easilygelledcomprising preparing a mixture which comprises boric acid, agelling agent, an aqueous medium, an oxidizer, a fuel component, andsaid liquid, adjusting the pH of said mixture to between 1.5 and 4.4,blending said mixture well, and adjusting the pH of said mixture tobetween 4.5 and 7.

25. The method of claim 24 wherein said liquid not easily gelled is anitroparaffin.

26. The method of claim 25 wherein said nitroparaffin is nitromethane.

27. A method of controlling the degree of gelation of the composition ofclaim 6 comprising adjusting the pH of said composition.

(g 12 9 UNH'HE sTfiTE TE? FEQE C Patent No. 1 3 1 Dated f p 1972Inventor(s) Donald W. Edwards It is certified phat error appears in theabpve-identif1edpatent I and that said Letters Patent are herebycorrected as shown below:

Column 2, line 64, "preferably" should read -{preferable Column 4, undersection COMMENTS FOR TABLES I AND II, Item 2',

"trademark "X0589""should read trademark Jaguar EX-JB Column 4, undersection COMMENTS FOR TABLES I AND II, Item 4, "705D--AA" should read"705D-A" Column 4, line 41, l0 to ll should read l0 and 11 The tablebridging Columns 5 and 6, i at approximately line 41 should be labeledTABLE III d In said table above (TABLE III) bridging Columns 5 and 6, atapproximately line 42 the column headings "H I I K" should read H I JKand so on.

In said table above (TABLE III) bridging Columns 5 and 6, under tableheading Composition, percent, Ethylene diamine dinitrte' should readEthylene diamine dinitrate Signed and sealed this 5th day of December1972.

(SEAL) Attest:

EDWARDMQFLETQHERJRQ 7 ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents 33 3 UNITED STATES PATENT omen I CERTIFICATE OF CORRECTIONPatent; N0. Datgd 4,

Inventor(s) Donald W. Edwards It is certified that verror 8PPears in theebpv e- -identified'patent and that said Letters Patent are herebycorrected as shown'below:

Column 2, line 64,"preferably" should read pref erable Column 4, undersection COMMENTS FOR TABLES I AND II Item 2, "trademark "XO589"" shouldread trademark Jaguar EX-JB Column 4, under section COMMENTS FOR TABLES"I AND II, Item 4, "705D-AA" should read "705D-A" Column 4, line 41, "l0to 11" should read l0 and 11 The table bridging Columns 5 and 6 atapproximately line 41' should be labeled TABLE III In said table above(TABLE III) bridgingColumns 5 and 6, at approximately line 42 the columnheadings "H I I I 'K" should read H I J K--and so on.

In said table above (TABLE III) bridging Columns 5 and 6, under tableheading Composition, percent, "Ethylen'e diamine dinitrte" should readEthylene diamine dinitrate Signed andsealed this 5th day of Deoember1972. Q

(SEAL) Attest:

LEDWARDMJLETCHEBJR. I ROBERT GOTTSCHALK J Attestlng Officer-Commissioner of Patents

2. A composition according to claim 1 which contains a sensitizer. 3.The composition of claim 1 wherein said boric acid is obtained byacidifying borax.
 4. The composition of claim 1 wherein said gellingagent is a polysaccharide.
 5. The composition of claim 4 wherein saidpolysaccharide is a galactomannan.
 6. The composition of claim 5 whereinsaid galactomannan is guar gum.
 7. An explosive composition comprising 1pbw oxidizer, about 0.14 to about 0.43 pbw water, about 0.007 to about0.4 parts per part of water of a two-component mixture about 20 to 80percent of which is boric acid and about 20 to 80 percent of which is agelling agent, and a sufficient amount of a fuel component to give anoxygen balance between about +10 and -30.
 8. The composition of claim 7wherein said boric acid is obtained by acidifying borax.
 9. Acomposition according to claim 7 wherein about 0.007 to about 2.5 pbw ofa sensitizer is present.
 10. A composition according to claim 9 whereinsaid sensitizer is a combination of an air-entrapping material and anexplosive.
 11. The composition of claim 10 wherein said air-entrappingmaterial is phenol formaldehyde or glass micro-spheres.
 12. Thecomposition of claim 7 wherein said gelling agent comprises apolysaccharide.
 13. The composition of claim 12 wherein saidpolysaccharide is a galactomannan.
 14. The composition of claim 12wherein said galactomannan is guar gum.
 15. A method of controlling thedegree of gelation of an explosive composition comprised of boric acid,a gelling agent, and water, comprising raising the pH of saidcomposition to increase the degree of gelation and lowering the pH todecrease the degree of gelation.
 16. The method of claim 15 wherein saidpH is adjusted to about 4.5 to
 7. 17. The method of claim 16 whereinsaid composition contains an oxidizer and a fuel component and isdetonable.
 18. The method of claim 17 wherein said gelling agentcomprises a polysaccharide.
 19. The method of claim 18 wherein saidpolysaccharide is a glactomannan.
 20. The method of claim 19 whereinsaid galactomannan is guar gum.
 21. The method of claim 17 wherein thepH is adjusted by lowering it to below about 4.5 and then raising ituntil a gel of the desired consistency is obtained.
 22. The method ofclaim 17 wherein said composition is heated while being gelled.
 23. Themethod of claim 22 wherein said composition is heated to 100* to 180* F.24. A method of controlling the degree of gelation of an explosivecomposition which comprises boric acid, a gelling agent, an aqueousmedium, an oxidizer, a fuel component, and a liquid not easily gelledcomprising preparing a mixture which comprises boric acid, a gellingagent, an aqueous medium, an oxidizer, a fuel component, and saidliquid, adjusting the pH of said mixture to between 1.5 and 4.4,blending said mixture well, and adjusting the pH of said mixture tobetween 4.5 and
 7. 25. The method of claim 24 wherein said liquid noteasily gelled is a nitroparaffin.
 26. The method of claim 25 whereinsaid nitroparaffin is nitromethane.
 27. A method of controlling thedegree of gelation of the composition of claim 6 comprising adjustingthe pH of said composition.